While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.

Background

Inonotus obliquus, a mushroom commonly known as "chaga," is widely used in folk medicine in Siberia, North America, and northern Europe. Chaga is a member of the Basidiomycetes (true mushrooms) family and widely distributed in Europe, Russia, and the northern regions of Japan. When growing on the tree, chaga produces a black, long-lasting woody growth called a "conk," which absorbs nutrients and important chemicals from the wood. When the chaga conk flower ripens, it falls to the forest floor. It is estimated that only about 0.025% of trees will grow a chaga conk, making the chaga mushroom somewhat rare.

Chaga mushrooms have been used in folk medicine since the 16th Century as a remedy for cancer, stomach problems, ulcers, and tuberculosis of the bones. Chaga has been collected and consumed for centuries in Asia. Although medicinal use of chaga and other mushrooms is rare in Western countries, reports have described its nutritional value and the value of the biologically active starches and other plant compounds (flavonoids and lipids) that it contains.

Some reports describe chaga as having the following effects: antibacterial; antiviral; toxic; immune system-regulating; anticancer; cardiovascular; pain-relieving; blood sugar-lowering; and plant, insect, or worm-killing activities. However, there is currently a lack of evidence to support using chaga to treat any medical condition.

Scientific Evidence

Uses

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Grade*

No available studies qualify for inclusion in the evidence table.

*Key to grades:A: Strong scientific evidence for this use; B: Good scientific evidence for this use; C: Unclear scientific evidence for this use; D: Fair scientific evidence against this use (it may not work); F: Strong scientific evidence against this use (it likely does not work).

Tradition/Theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)

To reduce illness, 7-10 grams of powdered chaga extract has been taken daily by mouth. One teaspoon of crushed chaga in one cup of water has been taken three times daily to improve health. Also, 8-10 drops of chaga have been taken two times daily to treat general sickness.

For the immune system, 10 drops of chaga extract with a beverage twice daily have been used.

To prevent illness, 2-3 grams of powdered chaga extract daily has been used in healthy people.

Children (under 18 years old)

There is no proven safe or effective dose for chaga in children.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people with a known allergy or sensitivity to chaga, its constituents, or any member of the Hymenochaetaceae family.

Side Effects and Warnings

Chaga may lower blood sugar and increase insulin levels. Caution is advised in people with diabetes or low blood sugar, as well as those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Chaga may increase the risk of bleeding. Caution is advised in people with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Avoid in patients with known allergy or sensitivity to chaga, its constituents, or any member of the Hymenochaetaceae family.

Pregnancy and Breastfeeding

There is currently a lack of scientific evidence on the use of chaga during pregnancy or lactation.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

Although not well studied in humans, chaga may prevent blood clotting and may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve).

Although it has not been well studied in humans, chaga may lower blood sugar levels and increase insulin levels. Caution is advised when using medications that may also lower blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Chaga may also interact with agents that affect the immune system, anticancer agents, anti-inflammatory agents, and cholesterol-lowering agents.

Interactions with Herbs and Dietary Supplements

Although not well studied in humans, chaga may prevent blood clotting and may increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Although not well studied in humans, chaga may lower blood sugar levels and increase insulin levels. Caution is advised when using supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Chaga may also interact with anticancer herbs and supplements, anti-inflammatory herbs and supplements, antioxidants, cholesterol-lowering herbs and supplements, and herbs and supplements that affect the immune system.

Author Information

This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.